Conventionally, substances imparting stimulating sensory feeling (pungent sensation) and warming sensory feeling (warming sensation) to the skin, oral cavity, nose and throat of a person, so-called sensory stimulants, have been used for toothpastes, confectionery (e.g. chewing gum and candies), tobacco, cataplasm products, bath agents, and cosmetics. As a compound which imparts such pungent and warming sensations, there has been known a vanillyl alcohol derivative (hereinafter, abbreviated as VE in some cases) represented by the following general formula (2):
wherein R represents an alkyl group having 1 to 6 carbon atoms, and ‘Me’ represents a methyl group, hereinafter the same. In addition, Japanese Patent Application Laid-Open No. 57-009729 (JP-A-57-009729) discloses that the compound has a strong pungent and/or warming sensation effect and JP-A-57-082308 discloses that the compound emphasizes a cooling sensation effect of menthol.
Although the VEs have the strong pungent and/or warming sensation effect, they also have problems that they are easy to be colored under the basic condition and that coloration and taste alteration are easily caused with the lapse of time. Therefore, in the addition of VE to commercial products, the amount of VE and the kind of product to be added are limited. Further, since the complicated reaction steps such as reduction and etherification of vanillin are needed in the production of VE, it has been desired to provide a sensory stimulant easy to produce and excellent in the effect.
On the other hand, vanillin propylene glycol acetal has been conventionally known as a vanillin acetal compound (refer to JP-A-2003-137758). However, it is simply exemplified as a fragrance for hair treatment cosmetics, and the sensory stimulating effect thereof has been unknown. Further, although it has been known that a vanillin acetal compound, vanillin 2,3-butanediol acetal, is used as a fragrance agent (refer to JP-A-2001-002673), a sensory stimulating effect of this compound has also been unknown.
Further, JP-A-8-225564 discloses, as a sensory stimulant, 4-(l-menthoxymethyl)-2-phenyl-1,3-dioxolane and its derivatives represented by the following general formula (3):
wherein R1 represents a hydrogen atom, a hydroxyl group, or a lower alkoxy group; R2 and R3 may be same or different and independently represent a hydrogen atom, a hydroxyl group, or a lower alkoxy group, or R2 and R3 are bonded to each other to form a methylenedioxy group. However, their effect is not sufficient, and therefore it has been desired to obtain a compound having a more excellent pungent and/or warming sensation effect and cooling sensation-emphasizing effect.
As described above, sensory stimulants having the pungent and/or warming sensation effect and additionally the cooling sensation-emphasizing effect have been known conventionally. However, these conventionally known sensory stimulants have problems, that is, they easily cause coloration and taste alteration with the lapse of time or in accordance with the use conditions; the production process includes the complicated reaction steps; the pungent and/or warming sensation effect and a lasting effect thereof are insufficient; and the cooling sensation-emphasizing effect is insufficient. It has been desired to solve these problems.